The present invention relates to a nozzle device, and especially to nozzles the opening of which do not face to the vent of the compressing chamber of the vacuum pump. Therefore, particles deposited in the vacuum pump are reduced and the gas resistance is also reduced.
In the manufacturing process of semiconductors, vacuum systems are widely used. For example, manufacturing process equipment, for dry etching, ion implantation, and thin film deposition includes expensive machines to be operated in a proper vacuum environment. For the vacuum pump used in the operation of semiconductor plant, the tolerance of the pump is an important consideration. The manufacturing gas will induce particles in the gas channel of a vacuum pump so that the lifetime of a vacuum pump is effected. Therefore, there is an eager demand to reduce the deposition of particles in the gas channel of a vacuum pump.
In this specification, a mechanical vacuum pump is considered. Wherein, a mechanical operation serves to pump gas from the compressing air, then the gas is transferred, compressed, and vented in the pump. Therefore, the effect of vacuuming is achieved. Referring to FIGS. 1 and 2, the vacuum pump 1 is a mechanical Root vacuum pump, which includes rotors 12 rotating within a compressing chamber 11. The rotors 12 and the housing 13 form the gas inlet 14 and gas outlet 15 of the compressing chamber 11. By the driving of the timing gear, the two rotors 12 have equal rotary speeds (a ratio of 1:1). The outlook design of the two rotors 12 has a 1:1 tooth ratio. During the operating process, the two rotors 12 retain a predetermined gap. Therefore, gas can be pumped from the compressing chamber. The performance of the vacuum pump 1 is determined from the precision of the gap of rotors 12. The processing gas is capable of generating particles through reaction in the gas channel of the vacuum pump. Thus, the danger from the deposition of the particles to cause the rotor to seize is decreased so that the vacuum pump must be arranged with a device for purging particles. In general, purging nitrogen is guided into the channel for exhausting particles. A prior art nozzle device used in a roots vacuum pump had a nozzle for spraying purging gas and facing the vent of the compressing chamber. Therefore, particles are easily blown into the compressing chamber. However, this will induce that the rotor to be seized. Besides, the tapered portions directly face the vent, the gas resistance will increase so as to reduce the pumping speed.